You have Team Tieu we based out of Gymbox (Bank, Farringdon, Holborn, Covent Garden, Westfield Shepherds Bush) and classes are across all 5 gyms from morning, lunch and evening, also the fighters train at 2pm monday to friday

There's also MMA Clinic in Angel and Chris Carley who trained quite a few world champions teaches Muay Thai think twice a week.

You have K.O gym at bethnal green

There is also Snipers Gym and Nomads somewhere around the north of london area but not to sure where.

Kilen Dang Muay Thai train out of Gracie Garcia Dojo in the Cameron Building, 12 Castlehaven Road. Bang in the middle of Camden Road, Camden Town and Chalk Farm stations. The instructor is called Gavin Davis. He learned his trade with Team Kaobon in Liverpool and is very good.